1. Field of the Invention
The present invention relates to an improvement in the image forming apparatus such as electrophotographic copier, and more particularly to an image forming apparatus in which the image formation is controlled by a digital computer.
2. Description of the Prior Art
In the conventional image forming apparatus it has not been possible to identify which parts of the image formation are controlled by the digital computer. Also there has been no effective method for identifying whether the digital computer is performing normal control in response to the input signals, or receiving normal input signals.
Also in the image forming apparatus in which the image formation is controlled by the output of an electrometer for measuring the surface potential of an electrostatic latent image formed on a recording member such as a photosensitive member or an insulating member, it has been necessary to use a voltmeter or the like for measuring the actual output of the electrometer.